package com.example.demo.test;

import java.util.concurrent.ThreadPoolExecutor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

/**
 * 默认情况下，在创建了线程池后，线程池中的线程数为0，当有任务来之后，就会创建一个线程去执行任务， 当线程池中的线程数目达到corePoolSize后，就会把到达的任务放到缓存队列当中； 当队列满了，就继续创建线程，当线程数量大于等于maxPoolSize后，开始使用拒绝策略拒绝
 *
 * @author Jensen Zhan
 */
@Configuration
@EnableAsync
public class ThreadPoolTaskConfig {

    /**
     * 默认线程数
     */
    private static final int CORE_POOL_SIZE = 20;
    /**
     * 最大线程数
     */
    private static final int MAX_POOL_SIZE = 100;
    /**
     * 允许线程空闲时间(单位:默认为秒)
     */
    private static final int KEEP_ALIVE_TIME = 10;
    /**
     * 缓冲队列大小
     */
    private static final int QUEUE_CAPACITY = 200;
    /**
     * 线程池名前缀
     */
    private static final String THREAD_NAME_PREFIX = "Async-Service-";

    @Bean
    public ThreadPoolTaskExecutor taskExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(CORE_POOL_SIZE);
        executor.setMaxPoolSize(MAX_POOL_SIZE);
        executor.setQueueCapacity(QUEUE_CAPACITY);
        executor.setKeepAliveSeconds(KEEP_ALIVE_TIME);
        executor.setThreadNamePrefix(THREAD_NAME_PREFIX);
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        executor.initialize();
        return executor;
    }

}
